In wireless communication systems, RRM is generally responsible for utilizing the air interface resources. RRM is used to guarantee quality of service (QoS), to provide efficient use of the radio resources, and to increase system capacity. RRM consists of admission control, handover, power control, and congestion control functionalities. Admission control can be divided into user admission control and call admission control (CAC). User admission control accepts or rejects the radio resource control (RRC) connection requested by a wireless transmit/receive unit (WTRU). CAC accepts or rejects a request to establish or modify a radio access bearer (RAB) in the radio access network (RAN). CAC is located in the controlling radio network controller (C-RNC).
Dynamic channel allocation (DCA) is used to meet the ever increasing cellular traffic demand. There are two DCA functions, slow DCA (S-DCA) and fast DCA (F-DCA). The S-DCA allocates the radio resources to cells, while the F-DCA allocates the radio resources to bearer service. The F-DCA CAC functions are responsible for efficiently allocating or changing the allocations of physical resources. When a request for physical resources is received, the CAC will accept or reject the request based on the availability of physical resources and interference level in the cell. The request can be accepted only if both uplink and downlink CAC admit it. Otherwise, the request is rejected.
For time division duplex (TDD) mode, the radio link setup procedure is used to establish the necessary radio resources for a new radio link related to real time (RT) or non real time (NRT) services. After the radio link is set up, the radio link reconfiguration procedure is used to add, modify, or delete any physical resources for this existing radio link. The F-DCA CAC algorithm is invoked upon receiving the request messages.
In order to guarantee the QoS and minimize the interference, a certain F-DCA CAC algorithm has been currently implemented. But the previous implementation of the F-DCA CAC algorithm has several limitations. One limitation is that it is difficult to be reused by other RRM functions since the main interface function is large, and the inputs to the code allocation function (which forms the core function of the F-DCA CAC algorithm), are dependent on the signal message. A second limitation is that the past implementation of the F-DCA CAC algorithm is generally only suitable for RT service.
It is desirable to provide an optimized implementation of the F-DCA CAC algorithm for radio link reconfiguration which is suitable for RT and NRT service, and which overcomes the disadvantages of the known algorithms.